Pest control



FlCE

STATES PEST CONTROL Frank H. Kaufert, St. Paul, Minn asslgnor to 113. ll. du Pont de Nemours & Company, Wilmington, Del, a corporation of Delaware No Drawing. Application July 3, 1940, Serial No. 343,775

3 Claims. (01. 167-30) This invention relates to pest control and is particularly directed to methods and composidiphenylamine seem to undergo deterioration and tions for preventing or arresting infestations of become inactivated in the soil. Other materials insects, fungi, bacteria, protozoa, molds and varisuch as the chlorinated phenols and nitro'phenols ous other organisms economically harmful to 5 are not only hazardous to use but frequently man which commonly infest organic matter, sufier the disadvantages of both the soluble and whether plant or animal or of plant or animal insoluble type in view of the solubilizing effect of origin, either in the natural, fabricated or synalkali in the soil. thetic state; which methods and compositions The ideal toxicant for a soil poison for termites distinguish from the processes and compositions is one which is water-insoluble and substantially known heretofore in the use of chlorinated inert to the constituents of the soil and the e t t atmosphere, which is not so volatile as to become More particularly this invention relates to the ineiTective in a relatively short time, and which is control of noxious organisms which infest soil, so highly toxic to termites that notwithstanding such as termites, eelworms, fungi and the like, its slight volatility it is effective in relatively and to soil poisoning or disinfecting compositions small concentrations. The ideal toxicant addicontaining as an essential active ingredient a tionally should be easily applied, that is, it should chlorinated fi-nitrotoluene having an equivalent be a liquid or highly soluble in cheap solvents, or molecular weight less than 200. it should be easily emulsified. Also, it'should be T mite infest the greater portion of the safe tohandle in the sense of not creating fire United States and other warm or temperate hazards or causing injury to human beings or to places, and because of their peculiar habit of ornamental plants and shrubbery. ve it living in subterranean retreats from which they should be cheap and readily available. infest wooden buildings and constructions with- Now it has been found that the chlorinated out overtly giving any indication of their presnitrotoluenes have properties which make them once, create problems of control which are not eminently suited for the control of certain types generally encountered with other types of pests. of pe p t y termites and fungi and Because the presence of termites is seldom dis that their cheapness and availability C p covered until substantial damage has been done with their toxicological and P y a p pe t the best means of control has been by the use of 39 combine to make them suited to the control of preventive measures, and various allegedly tera wide variety of pestiferous organisms. mite-proof constructions have been proposed and The chlorinated nitrotoluenes to which this are in common 1159- However h Control is invention is particularly directed are obtainable effected whether b use of termite shields by the chlorination of fi-nitrotoluene which, other means, or by eradication or by prevention, when carried out according to methods Well it is now generally recognized that the control is known to those skilled in the art, yield both more; efictwe 'i reliajble if the sufrouPdmg mono and polychlorinated derivatives. If the ti g-F 3 f i l i g lg 3: monochlorination is practiced the product is a e m mg or cons luc Ion 15 ed W as 4,0 mixture of two isomers, namely, 2-chloro-6-niable soil poison. I

. trotoluene and -chloro-fi-nitrotoluene, which A substance toxic to termites and incorporated may be utilized as such or separated by mm? in a vehicle suitable for impregnating the soil may act to kill the termites or at least to prevent t'lonal crystamzitmn or other know? them from infesting the building or construction to thjose sklned m m In 5011 termites, however, it is desirable that the equivaby diffusing into the subterranean passages and retreats of the termites through its volatility, lent molecular welght 0f t Compound 511011101 not exceed about 200, since otherwise the prodwater-solubility and like properties. Watersoluble soil poisons such as sodium arsenite, while ets a e not suflic e t volatile- In other caseshighly eiiective, suffer disadvantages in that they 88 he e the product is used as a preservative tend to leach out during weathering and also tend and disinfectant for wood, wallboard, rope, fabto pollute water supplies. Water-soluble come t e fi P pe P regenerated pounds, and the water solubility need only be s c-l to prevent attack vby small, are more likely also to cause injury to fun s, bacteria a other harmful ornamental plants. Water-insoluble compounds organisms, a product of relatively high molecsuch as ortho-dichlorobenzene and the chlorol r wei h i more desirable he r e Of pentanes are more commonly employed but also chlorination and nitrationcan be adjusted as sufier disadvantages in that because of high desired to give a product most suited for the volatility they do not afiord protection for a particular application.

sufficient length of time. Also, many of the The comparative effectiveness of the chlorinknown soil poisons such as beta-naphthol andated nltrotoluenes as soil poisons for termites is shown in the following example:

EXAHPLI 1 Description Termites all dead-little penetration into soil.

Termites all dead-deep penetration into soil.

Malarityh (b%+) termites dead-little penetration in so Mo grlty (5093+) termites dead-deep penetration into Mlilofityfl termites alive (9o%+)littlc penet ration toso Majority termites alive (90%+)-deep penetration into soil.

The results obtained in three series of tests, one of which was conducted for six months, another of which for four months, and thethird for one month, are given in the following table:

Series I (After six months) Concentration oi chemical in soil Compound Z-chloro-d-nitrotoluene... l0 l0 l0 6 Ortbodichlorobenuna.-. 0 0 0 0 0 Dlchloropentane 0 0 0 0 0 Alpho-nitromplithalone. 8 0 .0 0 0 Pontachloropbonol 4 0 0 0 Dipbonylamino 0 0 o 0 Series II-(After four months) Concentration of chemical in soil Compound moo 1:400 1:300 meoo 1am z-chloro o-nitrotoluone... i0 10 10 6 o-nltrotriehlorotoluone 8 4 0 6-chloro-2,3-dinitrotolmno 8 0 0 Orthodichlorobenzene-.- 8 0 0 0 Dicbloropentane 4. 0 0 0 Alpha-nitronaphthllene. 8 0 0 Series III (After one month) Concentration oi chemical in soil Compound moo 1:400 moo meoo 113200 2-obloro-6'nitmtoluenQ-- 10 10 1o 10 1g Monocblorinatod 6-111- 2 0 .i 2' o o It is indicated inthe above. data that the monochloro-mononitro derivatives are the most for applying these materials to soil may be prepared as follows:

Exams: 2

A concentrated emulsion suitable for preparing dilute spray emulsions is prepared by blending together 22 /2 parts-of 2-chloro-6-nitrotoluene, 2 parts ortho-dichlorobenzene and 25 parts straw paramn oil of viscosity 65 sec. Saybolt, to form a clear solution from which the 2-chloro-6-' nitrotoluene does not separate at normal temperatures, and emulsifying this oil solution in 49 parts of a casein-borax solution'prepared from 3 parts of borax and 6 parts of casein for each hundred parts of water. lauryl sulfate is also included and the emulsion is effected simply by passing all the components through a colloid mill. The product is a stable. highly concentrated emulsion which is sufficiently fluid to pour easily and which may be diluted with large quantities of water without breaking. It should be applied to the soil in dilution of 1 to 2 parts of the concentrate per 2 parts of the water. The amount required must be gauged by the experience of the'operator and in accordance with the comparative data given in the foregoing table.

The ortho-dichlorobenzene functions to reduce the melting point of the z-chloro-fi-nitrotoluene and to increase its solubility in the oil. If it is not used, more oil is required and the concentration of the 2-chloro-6-nitrotoluene in the dispersed phase is correspondingly reduced. The

spirits up to a mineral oil having a viscosity of other wetting agents in place of the sodium 110sec. Saybolt. Other emulsifying agents may be used in place of the solubilized casein and lauryl sulfate.

. Another suitable composition can be prepared according to the following example:

monochlorinated fi-nitrotoluene in 25 parts of straw paramn oil of viscosity of 65 sec. Saybolt 0 and emulsifying the solution thus obtained in the manner described in Example 2. The monochlorinated G-nitrotoluene is a. mixture of the 2- and- 4-chloro isomers. About of the mixture is 2-ch1oro-6-nitrotoluene. o-Dichloro- I so benzene is not used in'thls formulation because the presence of the 4-chloro-6-nitrotoluene has essentially the same effect in reducing the melting point and in increasing the miscibility of the product in the paraflln oil. The 6:4 ratio is determined by the chlorination procedure and may vary considerably. Also. it may be augmented by adding additional quantities of 2-chloro-6-nitrotoluene without detrimentally affecting the stability of the emulsion.

Another suitable composition is prepared according to the following example:

will 4 a composition which is self-dispersible is presuitable for soil poisons. Suitable comp it on 1s pared byblending together parts of monochlor- One part of sodiuminated 6-nitrotoluene and 15 parts of piperidine oleate. The product is a clear solution from which dilute emulsions may be easily prepared if precaution is taken first to prepare a concentrated emulsion. It is suitable to pour the product into an equal quantity of water, stir well and dilute with water as desired. One to 2 parts of the concentrate to each 10 parts of water provides an emulsion suitable for spraying termite infested soil.

In place of the monochlorinated G-nitrotoluene there can be substituted 2-chloro-6-nitrotoluene containing orthb-dichlorobenzene as described in Example 2. In either case paraffin oil or like solvent, as described in Example 2, may be used to reduce the concentration of chlorinated nitrotoluene in the dispersed phase. Other emulsifying agents may be used, but unlike Examples 2 and 3 these must be of the oil-miscible or oilsoluble types, or must be used in conjunction with a blending agent to solubilize them in the concentrate. An example of the latter type is N- diethyl-N-cyclohexylamine lauryl sulfate, which becomes oil-miscible when blended with a higher alcohol such as oleyl alcohol and other water-insoluble normally liquid alcohols. Other amine salts of the higher alcohol sulfates, as described in U. S. Patent 2,139,256, may be similarly employed. Other oil-soluble emulsifying agents include the sulfonated mineral oils and sulfonated vegetable oils such as Turkey-red oil.

While I have described my invention with particular reference to soil poisons for termites, it is to be understood that in its broader aspects the invention is not so limited but extends to and includes the use of chlorinated nitrotoluenes in the preservation of various products such as wood, wallboard, rope, fabric, leather, fish nets, paper, paint, regenerated cellulosic products, etc., from attack of fungi, insects, bacteria and like harmful organisms, particular applications of which are set forth in my copending application, Serial No. 343,820 filed of even date hereof.

I claim:

1. A termite soil poisoning and disinfecting composition containing as an essential active ingredient 2-chloro-6-nitrot0luene and {a carrier therefor.

2. A pest control composition comprising 2- chloro-6-nitrotoluene, ortho-dichlorobenzene and a mineral oil in proportions to'give a stable solution at normal temperatures.

3. The method of protecting wood and wood products from attack by termites which comprises impregnating the terrain surrounding the wood with 2-chloro-6-nitrotoluene. r

FRANK H. KAUFERT. 

